<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>3-2 css函数：attr</title>
  <style>
    .title::after {
      content: attr(href)
    }
  </style>
</head>

<body>
  <a class="title" href='www.google.com'>点我去谷歌</a>
</body>

</html>